Merge pull request #43 from gitpod-io/to/path-env

Ensure that `EnvVarCombineMergeUnique` keeps order

Author: kylos101

pkg/dazzle/combiner.go

@@ -311,14 +311,26 @@ func mergeEnv(base *ociv1.Image, others []*ociv1.Image, vars []EnvVarCombination
 				case EnvVarCombineMerge:
 					envs[k] += ":" + v
 				case EnvVarCombineMergeUnique:
-					vs := make(map[string]struct{})
-					for _, s := range strings.Split(envValue, ":") {
-						vs[s] = struct{}{}
+					var vs []string
+					vs = append(vs, strings.Split(envValue, ":")...)
+					vs = append(vs, strings.Split(v, ":")...)
+
+					var (
+						vss []string
+						idx = make(map[string]struct{})
+					)
+					lenVS := len(vs) - 1
+					for i := range vs {
+						v := vs[lenVS-i]
+						if _, exists := idx[v]; exists {
+							continue
+						}
+						idx[v] = struct{}{}
+						vss = append(vss, v)
 					}
-					vs[v] = struct{}{}
-					vss := make([]string, 0, len(vs))
-					for s := range vs {
-						vss = append(vss, s)
+
+					for i, j := 0, len(vss)-1; i < j; i, j = i+1, j-1 {
+						vss[i], vss[j] = vss[j], vss[i]
 					}
 					envs[k] = strings.Join(vss, ":")
 				}

pkg/dazzle/combiner_test.go

@@ -0,0 +1,182 @@
+// Copyright © 2020 Gitpod
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package dazzle
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	ociv1 "github.com/opencontainers/image-spec/specs-go/v1"
+)
+
+func TestMergeEnv(t *testing.T) {
+	tests := []struct {
+		name   string
+		base   *ociv1.Image
+		others []*ociv1.Image
+		vars   []EnvVarCombination
+		expect []string
+	}{
+		{
+			name: "EnvVarCombineMergeUnique",
+			base: &ociv1.Image{
+				Config: ociv1.ImageConfig{
+					Env: []string{
+						"PATH=first:second:third:common-value",
+					},
+				},
+			},
+			others: []*ociv1.Image{
+				{
+					Config: ociv1.ImageConfig{
+						Env: []string{
+							"PATH=fourth:fifth:common-value",
+						},
+					},
+				},
+				{
+					Config: ociv1.ImageConfig{
+						Env: []string{
+							"PATH=sixth:sixth:common-value",
+						},
+					},
+				},
+				{
+					Config: ociv1.ImageConfig{
+						Env: []string{
+							"PATH=eighth:seventh:eighth:common-value",
+						},
+					},
+				},
+			},
+			vars: []EnvVarCombination{
+				{
+					Name:   "PATH",
+					Action: EnvVarCombineMergeUnique,
+				},
+			},
+			expect: []string{"PATH=first:second:third:fourth:fifth:sixth:seventh:eighth:common-value"},
+		},
+		{
+			name: "EnvVarCombineMerge",
+			base: &ociv1.Image{
+				Config: ociv1.ImageConfig{
+					Env: []string{
+						"PATH=first:second:third:common-value",
+					},
+				},
+			},
+			others: []*ociv1.Image{
+				{
+					Config: ociv1.ImageConfig{
+						Env: []string{
+							"PATH=fourth:fifth:common-value",
+						},
+					},
+				},
+				{
+					Config: ociv1.ImageConfig{
+						Env: []string{
+							"PATH=sixth:sixth:common-value",
+						},
+					},
+				},
+				{
+					Config: ociv1.ImageConfig{
+						Env: []string{
+							"PATH=eighth:seventh:eighth:common-value",
+						},
+					},
+				},
+			},
+			vars: []EnvVarCombination{
+				{
+					Name:   "PATH",
+					Action: EnvVarCombineMerge,
+				},
+			},
+			expect: []string{"PATH=first:second:third:common-value:fourth:fifth:common-value:sixth:sixth:common-value:eighth:seventh:eighth:common-value"},
+		},
+		{
+			name: "EnvVarCombineUseLast",
+			base: &ociv1.Image{
+				Config: ociv1.ImageConfig{
+					Env: []string{
+						"PATH=first:second:third:common-value",
+					},
+				},
+			},
+			others: []*ociv1.Image{
+				{
+					Config: ociv1.ImageConfig{
+						Env: []string{
+							"PATH=fourth:fifth:common-value",
+						},
+					},
+				},
+			},
+			vars: []EnvVarCombination{
+				{
+					Name:   "PATH",
+					Action: EnvVarCombineUseLast,
+				},
+			},
+			expect: []string{"PATH=fourth:fifth:common-value"},
+		},
+		{
+			name: "EnvVarCombineUseFirst",
+			base: &ociv1.Image{
+				Config: ociv1.ImageConfig{
+					Env: []string{
+						"PATH=first:second:third:common-value",
+					},
+				},
+			},
+			others: []*ociv1.Image{
+				{
+					Config: ociv1.ImageConfig{
+						Env: []string{
+							"PATH=fourth:fifth:common-value",
+						},
+					},
+				},
+			},
+			vars: []EnvVarCombination{
+				{
+					Name:   "PATH",
+					Action: EnvVarCombineUseFirst,
+				},
+			},
+			expect: []string{"PATH=first:second:third:common-value"},
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			envs, err := mergeEnv(test.base, test.others, test.vars)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if diff := cmp.Diff(envs, test.expect); len(diff) != 0 {
+				t.Errorf("mergeEnv() mismatch (-want +got):\n%s", diff)
+			}
+		})
+	}
+}